CVE-2026-46669: `openvm-pairing` pairing check missing proper subfield check on scaling factor

Synopsis

A cryptographic integrity bypass affects the openvm-pairing guest library in the OpenVM zkVM framework (versions before 1.6.0). The vulnerability is reachable over the network with no authentication required, and stems from the try_honest_pairing_check function failing to verify that the scaling factor s is an element of the correct subfield of Fp12 when executing a pairing check. Successful exploitation allows an attacker to cause the pairing check to return an incorrect result, meaning invalid cryptographic proofs can be accepted as valid, breaking the integrity guarantees of any system relying on that check. HarborGuard tracks this advisory and will make a patched-image rebuild available at version 1.6.0 as soon as affected images are identified in customer environments.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The affected library is exposed over the network, meaning an attacker can send crafted inputs to a pairing check endpoint without requiring local or adjacent-network access.

• AuthenticationNot required

  No authentication is needed; the attacker can interact with the vulnerable pairing check function anonymously.

• Victim interactionNot required

  Exploitation requires no action from a user or operator; the attacker triggers the faulty check directly.

• Attack complexityDetail

  Attack complexity is low, meaning the exploit is reliable and does not depend on race conditions, specific memory layout, or other environmental prerequisites.

Blast Radius

• An attacker can submit an invalid cryptographic proof that the pairing check accepts as valid, breaking the soundness guarantee of any zkVM circuit relying on this function.
• Any downstream system that trusts pairing-check results (smart contracts, proof verifiers, bridge validators) can be made to accept fraudulent state transitions or falsified computations.
• Integrity of all data or transaction state guarded by proofs generated under the affected library version is undermined, since the verification step can be silently defeated.